Boiler internal fuse keeps blowing together with the pump

[andytw]

Aha OK. So it sounds as if there is not a circuit from live to earth after all.
I would go for the test with mains on the motor and see what happens.

Do I understand that the pump body is still the original ?
If this is stiff then it could be putting undue load on the motor.
Apologies if this has been mentioned.

andytw

 

[matt1e]

Have you ruled out any external wiring?
Disconnect it and fit a link, replace the fuse then start fault finding from there

Matt

 

[Agile]

OP, I am sorry to say you are completely out of your depth!

You have ftted a time delay fuse when the maker specifies a fast blow.

Nor do you know how to use your multimeter. Even if you did then you would not know how to interpret it.

You have employed a nupty repairer.

On here you have not received useful or correct assistance either.

The only sensible thing to do is to either employ a competent engineer if you can find one, or go for a fixed price repair brom British Gas or even Sime if they do one. If they change good parts or blow up the pump or PCB then at least you dont have to pay for that.

Tony

 

[andytw]

On here you have not received useful or correct assistance either.

Tony

Nice one. Time served expert speaking by any chance ??

 

[Agile]

[

So looking at these figures at face value you have 26 ohms between live and neutral which probably is about correct. The load is inductive so the actual resistance is only a guide.

andytw

Cane you name any 230v pump which has a winding resistance of 26 Ω ?

 

[matt1e]

On here you have not received useful or correct assistance either.

Tony

So are you saying it's a bad idea to disconnect and link out any external wiring in situations like this then Mr G

 

[Agile]

The PCB was marked T3A so I fitted a 3A fuse. What I didn't realise was that that the T designates time delay or slow blow fuse. Once I fitted the correct fuse it was fine.

andytw

Questionable that you should be fiddling with TVs if you dont understand the characteristics of different fuse types!

 

[Agile]

On here you have not received useful or correct assistance either.

Tony

So are you saying it's a bad idea to disconnect and link out any external wiring in situations like this then Mr G

Its fine to run a pump from a seperate mains supply fused at three or less amps.

Neither the OP nor his "plumber" ever tried that. It would have been a sensible thing to do initially and might have saved fitting three new pumps!

I often wonder if some of these nupties do that so they can take away the old one and reuse that elsewhere. It certainly goes on in the motor trade!

 

[ianmcd]

On here you have not received useful or correct assistance either.

Tony

So are you saying it's a bad idea to disconnect and link out any external wiring in situations like this then Mr G

Its fine to run a pump from a seperate mains supply fused at three or less amps.

Neither the OP nor his "plumber" ever tried that. It would have been a sensible thing to do initially and might have saved fitting three new pumps!

I often wonder if some of these nupties do that so they can take away the old one and reuse that elsewhere. It certainly goes on in the motor trade!

I cant understand how he managed to fit a Grunny as its a Wilo in that boiler and the heads are different sizes ?

 

[andytw]

The PCB was marked T3A so I fitted a 3A fuse. What I didn't realise was that that the T designates time delay or slow blow fuse. Once I fitted the correct fuse it was fine.

andytw

Questionable that you should be fiddling with TVs if you dont understand the characteristics of different fuse types!

I wasn't actually fiddling with it. I changed the switch mode power supply FET as that had blown the fuse. I am quite happy to own up to my mistake, but hasten to add that I resolved it myself, on my own, without a forum. As I said I did not know that a T was a time delay fuse. No doubt I will learn something tomorrow.

xx

 

[matt1e]

On here you have not received useful or correct assistance either.

Tony

So are you saying it's a bad idea to disconnect and link out any external wiring in situations like this then Mr G

Its fine to run a pump from a seperate mains supply fused at three or less amps.

Neither the OP nor his "plumber" ever tried that. It would have been a sensible thing to do initially and might have saved fitting three new pumps!

I often wonder if some of these nupties do that so they can take away the old one and reuse that elsewhere. It certainly goes on in the motor trade!

That's not what I meant but I agree with you anyhow
What I meant by disconnecting external wiring was as in external control wiring i.e stats, programmers etc

Matt

 

[Agile]

I cant understand how he managed to fit a Grunny as its a Wilo in that boiler and the heads are different sizes ?

My guess is that someone had replaced the whole pump with a Grundfos pump previously.

That would explain why he was able to fit the "Bosch" pump head as I think that they are also made by Grundfos !

Its always nice to learn that some boilers like the Vokera will also take a standard Grunfoss pump head.

 

[andytw]

[

So looking at these figures at face value you have 26 ohms between live and neutral which probably is about correct. The load is inductive so the actual resistance is only a guide.

andytw

Cane you name any 230v pump which has a winding resistance of 26 Ω ?

Yep got me there. I was kind of sidetracked on the 1 ohm between Live and Earth.
Not sure which of these is the best way forward though

1. employ a competent engineer if you can find one, ... Bit open
2. or go for a fixed price repair brom British Gas ... they get slagged off by the experts on this and other forums all the time
3. or even Sime if they do one ... worth a punt but you don't sound optimistic

 

[twgas]

We (BG) get slagged off for, primarily, trying to sell stuff that in some people's eyes in not wanted or needed, however the independents on here often give the same advice but they do it to earn a living so its ok. I'm not tarring everyone with the same brush as there are good, and not-so-good "heating engineers" both within BG and other companies all the way down to independents.

 

[ianmcd]

I cant understand how he managed to fit a Grunny as its a Wilo in that boiler and the heads are different sizes ?

My guess is that someone had replaced the whole pump with a Grundfos pump previously.

That would explain why he was able to fit the "Bosch" pump head as I think that they are also made by Grundfos !

Its always nice to learn that some boilers like the Vokera will also take a standard Grunfoss pump head.

But thats not possible the pump head is a Wilo but the body is plastic and not a standard pump body its unique to the boiler and incorporates the AAV cost an arm and a leg to buy the complete unit